Electron tube



May 15, 1945- w. w. ElTEL ET AL ELECTRON TUBE Original Filed Feb. 14, 1941 wvA 1 TEL (2/81 086/! INVENTORS WILL/AM w E JACKAMEC BY a 2 THEIR ATTORNEY Patented May l5, 1 945 ELECTRON TUBE William W. Eitel. San Bruno, and Jack A. Me- Cullough, Millbrae, Callf., assignorct Elmtion of California McCullough, Inc., San Bruno, Caliit, a corpora- Original application February 14, 1941, Serial No.

378,900. Divided and this application December 21, 1943, Serial No. 515,186

7 Claims.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following de-.

scription of our invention. It is to be understood that we do not limit ourselves to this disclosure of species of our invention as we may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawing;

Figure 1 is a side view, partly in section and partly in elevation, showing a two unit tube embodying the invention.

Figure 2 is a fragmentary vertical sectional view showing a modified construction in which the plates are unitarily supported; and

Figure 3 is a detail horizontal sectional view of the same taken in a plane indicated by line 3-3 of Figure 2.

In terms of broad inclusion, our improved tube comprises an envelope, an anode structure supported in the envelope and having a tubular body, and a cap on one end of the body. The anode structure is provided with an aperture therein adjacent the capped end, whereby the inner end of another electrode projecting within the anode may be viewed during assembly to insure proper centering and alignment of the electrodes. Improved means are also provided for mounting the anode and other electrodes in the envelope.

In greater detail, and referring to Figure 1 of the drawing, the tube comprises an envelope of glass or the like having a cup-shaped upper section 2, intermediate section 3 with a reduced neck 4, and a lower section comprising a reentrant stem 6. These sections are made separately and subsequently fused together, the final seal being made between the upper and intermediate sections along seal 1 which lies in a plane transverse to the axes of the electrodes. Stem 6 carries an exhaust tubulation 9 through which the envelope is evacuated. The envelope is fitted with a'cup-shaped base H, say of porcelain, secured to neck 4 by a suitable cement l2. Prongs I3 of the usual type project from the base. It is understood that the envelope shown is merely for purposes of illustration, and that a different shape may be used.

Within the envelope are arranged a plurality of operative units, two triode units being shown in Figure 1, each unit comprising a plate I4,

grid [6 and cathode l1. The electrodes in each unit are coaxial, the axes of the two units being parallel and extending longitudially of the tu e. Our improved anode structure has a tubular body l4, preferably of sectional construction having heat radiating fins Hi. If desired however, the body may be a simple cylinder without fins. In order to provide a simplified mounting for the anode, and to prevent electron bombardment of the upper envelope wall, a dome shaped cap I9 is arranged at the upper end of body l4.X-This cap is preferably formed separately from the body and secured thereto by welding. It is understood that the cap and body may be integrally formed as by drawing the cap and body from a single sheet of metal. Each anode is preferably supported on its lead-in rod 2| by a bracket 23 adjacent the capped end of the anode. To provide the most eifective mount, lead 2| is arranged coaxial with the anode and bracket 23 is secured directly to cap l9. For convenience, the anode structure may be considered as constituted by the tubular body l4 and the cap l9, whether separately or integrally formed.

While the capped anode has definite advan- 1 tages for reasons already pointed out, the cap introduces a diificult problem in centering and aligning the cathode and grid. This will be appreciated because the latter electrodes pro-' ject up into the anode and there is no way of determining whether they are centered. Since proper functioning of the tube depends upon accurate alignment of the electrodes this struc ture introduces a major problem in tube manufacture. We have eliminated this difiiculty by providing apertures 25 adjacent the capped end of the anode structure. When the cap is formed separately from the body these apertures are preferably provided by arched recesses cut in the rim portion of the cap. In fabricating the tube the anodes are assembled in envelope dome portion 2 and the cathodes and grids are mounted on the other envelope portions. The final seal is made by bringing the cathodes and grids within the anodes and fusing the envelope -rods 36 sealed to stem 6.

together along seal 1. During this final sealing operation the operator observes the positions of the internal electrodes through apertures 25, thereby permitting him to accurately center these within the anodes while the seal is being made.

In the tube illustrated, grids 5 are of the cage type projecting into the open ends of the anodes and having lower ends terminating in base rings 24. Each grid is supported at the open end of the anode by a bracket 26 on a lead-in rod 21. These grid leads project downwardly through seals 28 at an annular ledge 29 formed in intermediate section 3 of the envelope. The lower ends of the grid leads are connected together byan external terminal ring 3| having tabs 32.welded to the leads and provided with a terminal button 33. This ring is L-shaped in section and is secured to the envelope at the shoulder by a suitable cement 34.

Filamentary cathodes II also project into the lower open ends of the anodes. Each comprises a helical coil of thoriated tungsten welded at top and bottom to a pair of tungsten lead-in Flexible extensions 3! connect the lower ends of leads 36 with corresponding pairs of base prongs I3.

Figures 2 and 3 disclose a modified construction in which anodes 14 are tied together and unitarily supported by a bracket 38 on a common anode lead 39. Openings 25 are provided adjacent the upper capped ends of the anodes in the manner previously described.

While we have chosen to illustrate the improved anode structure in a multiple unit tube, it is understood that the improvements may be incorporated in an ordinary single unit tube.

We claim:

1. An electron tube comprising an envelope, an anode structure in the envelope comprising a tubular body, and a cap on the upper end oi the body, said anode structure having an aperture therein adjacent the capped end and means supporting the anode structure projecting intothe envelope from its upper end and joined to said cap.

2. An electron tube comprising an envelope, an anode structure supported in the envelope comprising a, tubular body open at one end, a cap on the other end of the body, said anode structure having an aperture therein adjacent the capped end, and a cathode supported in the envelope independently of said anode structure projecting into the anode body with its inner end disposed adjacent said aperture.

3. An electron tube comprising an envelope, an anode structure supported in the envelope comprising a tubular body open at one end, a cap on the other end of the body, said anode structure having an aperture therein adjacent the capped end, and a cathode and grid supported in the envelope independently of said anode structure projecting into the anode body with their inner ends disposed adjacent said aperture.

4. An electron tube comprising an envelope, a tubular anode open at one end, a cap on the other end of the anode, an anode lead-in rod extending into the envelope, means adjacent the capped end of the anode and joined to the tubular body of the anode supporting it on said I rod, a free-ended cathode structure projecting into the open end of the anode, and conductor means for the cathode extending into the envelope.

5. An electron tube comprising an envelope, a tubular anode open at one end,'a cap on the other end of the anode, an anode lead-in rod extending into the envelope along the anode axis, means on said cap supporting the anode on said rod, a cathode projecting into the open end of' the anode, and conductor means for,

the cathode extending into the envelope.

6. An electron tube comprising an envelope, a tubular anode open at one end, a cap on the other end of the anode, free-ended cathode and grid structures projecting into the open end of the anode, anode and grid lead-in rods extending into the envelope, means adjacent the capped end of the anode supporting it on the anode lead-in rod, means adjacent the open end of the anode supporting the grid on the grid lead-in rod, said grid lead-in rod extending through the envelope wall at a point intermediate the ends of the envelope, and conductor means for the cathode extending into the envelope.

7. An electron tube comprising an envelope, a tubular anode in the envelope, anode conductor means projecting into an end of the envelope, a cap on the anode facing that end of the envelope into which the anode conductor means projects, means joining the cap and conductor means supporting the anode on said conductor means, a cathode extending into the end of the anode opposite said cap, and con ductor means for the cathode projecting into the envelope.

WILLIAM W. EITEL. JACK A. McCULLOUGH; 

